Inhaled hypertonic saline delivered by a heated nasal cannula

CONTINUING APPLICATION DATA

This application claims benefit to U.S. provisional application Ser. No. 60/978,887, filed on Oct. 10, 2007, and incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the aerosolized delivery of hypertonic saline (HS) and other osmolytes to provide overnight nasal hydration to patients with all forms of chronic obstructive pulmonary disease (COPD) over a long period of time. The present invention also relates to a device and apparatus with a sufficient reservoir to accomplish the same.

2. Description of the Background

The mucosal surfaces at the interface between the environment and the body have evolved a number of “innate defenses”, i.e., protective mechanisms. A principal form of such innate defense is to cleanse these surfaces with liquid. Typically, the quantity of the liquid layer on a mucosal surface reflects the balance between epithelial liquid secretion, often reflecting active anion (Cl⁻ and/or HCO₃⁻) secretion coupled with water (and a cation counter-ion), and epithelial liquid absorption, often reflecting active Na⁺ absorption, coupled with water and counter anion (Cl⁻ and/or HCO₃⁻). Many diseases of mucosal surfaces are caused by too little protective liquid on those mucosal surfaces created by an imbalance between secretion (too little) and absorption (relatively too much). The defective salt transport processes that characterize these mucosal dysfunctions reside in the epithelial layer of the mucosal surface.

One approach to replenish the protective liquid layer on mucosal surfaces is to “re-balance” the system by blocking Na⁺ channel and liquid absorption. The epithelial protein that mediates the rate-limiting step of Na⁺ and liquid absorption is the epithelial Na⁺ channel (ENaC). ENaC is positioned on the apical surface of the epithelium, i.e. the mucosal surface-environmental interface. Therefore, to inhibit ENaC mediated Na⁺ and liquid absorption, an ENaC blocker of the amiloride class (which blocks from the extracellular domain of ENaC) must be delivered to the mucosal surface and, importantly, be maintained at this site, to achieve therapeutic utility. The present invention describes diseases characterized by too little liquid on mucosal surfaces and “topical” sodium channel blockers designed to exhibit the increased potency, reduced mucosal absorbtion, and slow dissociation (“unbinding” or detachment) from ENaC required for therapy of these diseases.

Chronic obstructive pulmonary diseases are characterized by dehydration of airway surfaces and the retention of mucous secretions in the lungs. Examples of such diseases include cystic fibrosis, chronic bronchitis, and primary or secondary ciliary dyskinesia. Such diseases affect approximately 15 million patients in the United States, and are the sixth leading cause of death. Other airway or pulmonary diseases characterized by the accumulation of retained mucous secretions include sinusitis (an inflammation of the paranasal sinuses associated with upper respiratory infection) and pneumonia.

U.S. Pat. No. 5,817,028 to Anderson describes a method for the provocation of air passage narrowing (for evaluating susceptibility to asthma) and/or the induction of sputum in subjects via the inhalation of mannitol. It is suggested that the same technique can be used to induce sputum and promote mucociliary clearance. Substances suggested include osmolytes such as sodium chloride, potassium chloride, mannitol and dextrose.

Chronic bronchitis (CB), including the most common lethal genetic form of chronic bronchitis, cystic fibrosis (CF), a disease that reflects the body's failure to clear mucus normally from the lungs, which ultimately produces chronic airways infection. In the normal lung, the primary defense against chronic intrapulmonary airways infection (chronic bronchitis) is mediated by the continuous clearance of mucus from bronchial airway surfaces. This function in health effectively removes from the lung potentially noxious toxins and pathogens. Recent data indicate that the initiating problem, i.e., the “basic defect,” in both CB and CF is the failure to clear mucus from airway surfaces. The failure to clear mucus reflects dehydration of airway surfaces that reflects an imbalance between the amount of liquid and mucin on airway surfaces. This “airway surface liquid” (ASL) is primarily composed of salt and water in proportions similar to plasma (i.e., isotonic). Mucin macromolecules organize into a well defined “mucus layer” which normally traps inhaled bacteria and is transported out of the lung via the actions of cilia which beat in a watery, low viscosity solution termed the “periciliary liquid” (PCL). In the disease state, there is an imbalance in the quantities of mucins (too much) and ASL (too little) on airway surfaces that produces airway surface dehydration. This dehydration leads to mucus concentration, reduction in the lubricant activity of the PCL, and a failure to clear mucus via ciliary activity to the mouth. The reduction in mechanical clearance of mucus from the lung leads to chronic airways inflammation and bacterial colonization of mucus adherent to airway surfaces. It is the chronic retention of bacteria, the failure of local antimicrobial substances to kill mucus-entrapped bacteria on a chronic basis, and the consequent chronic inflammatory responses of the body to this type of surface infection, that lead to the destruction of the lung in CB and CF.

The current afflicted population in the U.S. is 12,000,000 patients with the acquired (primarily from cigarette smoke exposure) form of chronic bronchitis and approximately 30,000 patients with the genetic form, cystic fibrosis. Approximately equal numbers of both populations are present in Europe. In Asia, there is little CF but the incidence of CB is high and, like the rest of the world, is increasing.

There is currently a large, unmet medical need for products that specifically treat CB and CF at the level of the basic defect that cause these diseases. The current therapies for chronic bronchitis and cystic fibrosis focus on treating the symptoms and/or the late effects of these diseases. Thus, for chronic bronchitis, β-agonists, inhaled steroids, anti-cholinergic agents, and oral theophyllines and phosphodiesterase inhibitors are all in development. However, none of these drugs treat effectively the fundamental problem of the failure to clear mucus from the lung. Similarly, in cystic fibrosis, the same spectrum of pharmacologic agents is used. These strategies have been complemented by more recent strategies designed to clear the CF lung of the DNA (“Pulmozyme”; Genentech) that has been deposited in the lung by neutrophils that have futilely attempted to kill the bacteria that grow in adherent mucus masses and through the use of inhaled antibiotics (“TOBI”) designed to augment the lungs' own killing mechanisms to rid the adherent mucus plaques of bacteria. A general principle of the body is that if the initiating lesion is not treated, in this case mucus retention/obstruction, bacterial infections became chronic and increasingly refractory to antimicrobial therapy. Thus, a major unmet therapeutic need for both CB and CF lung diseases is an effective means of re-hydrating airway mucus (i.e., restoring/expanding the volume of the ASL) and promoting its clearance, with bacteria, from the lung.

The inhalation of osmolytes/osmolyte solutions, such as hypertonic saline (3-12% preferred embodiment 7%) has been demonstrated to be a safe and effective treatment for individuals with cystic fibrosis. Inhaled hypertonic saline improves mucus hydration and clearance, and is associated with improvements in lung function, as well as, a reduction in the number of infectious exacerbations over one year (Donaldson et al. N. Engl. J. Med. 354, 3, Jan. 19, 2006, pp. 241-250) and Elkins et. al. (N. Engl. J. Med. 354, 3, Jan. 19, 2006, pp. 229-240).

A limitation of inhaled osmolytes to increase mucosal hydration is the durability of the therapeutic effect of the osmolytes. In cell based assays, the ability of the mucosal epithelium to efficiently absorb fluid results in the reversal of osmolyte-induced surface hydration. The relatively short therapeutic benefit of inhaled osmolytes can be overcome by increasing the number of treatments per day. For example, Donaldson et al. (<i>N. Engl. J. Med. </i>354, 3, Jan. 19, 2006, pp. 241-250) showed inhaling 7% HS four times daily increased FEV1 by two fold greater than observed by Elkins et al. (<i>N. Engl. J. Med. </i>354, 3, Jan. 19, 2006, pp. 229-240) in CF patients inhaling 7% HS twice daily. However, increasing the dosing frequency of hypertonic saline or other osmolytes is inconvenient for subjects in need thereof, requiring hours of time taking medications during the day.

Clearly, what are needed are treatments that are more effective at restoring the clearance of mucus from the lungs of patients with CB/CF. The value of these new therapies will be reflected in improvements in the quality and duration of life for both the CF and the CB populations.

In U.S. patent application Ser. No. 11/851,803, R. C. Boucher and M. R. Johnson describe a method to extend the duration of osmolyte therapy by co-administering a potent sodium channel blockers. The inhibition of epithelial sodium transport prevents the reabsorption of HS osmolytes, and thereby, slows mucosal fluid absorption and extends the duration of mucosal hydration. The present invention describes an alternative approach to improving both the therapeutic benefit and convenience to the of inhaled osmolyte treatments.

SUMMARY OF THE INVENTION

The present invention is designed to improve the dosing of an osmolyte (e.g., HS) delivered to the lungs of subjects in need of airway surface rehydration by delivering the osmolyte to the lung via nasal cannulae. The present invention will permit subjects to be treated for long periods of time (e.g., hours) while sleeping or performing daily activities.

Thus, an object of the present invention is a method of treating chronic obstructive pulmonary disease by administering an effective amount of an aerosolized osmolyte to a subject in need thereof with a nebulizer connected to a nasal cannula.

Another object of the present invention is a nasal cannula system for delivering an osmolyte, comprising:

a nebulizer and

tubing, where one end of the tubing is connected to the nebulizer and another end of the tubing is tapered to fit in the nostril of a subject.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following FIGURE and detailed description.

BRIEF DESCRIPTION OF THE FIGURES

<figref idrefs="DRAWINGS">FIG. 1</figref>: Example of a nebulizer device capable of delivering osmolytes for extended periods of time. The diagram shows a standard large volume nebulizer (with &gt;100 ml capacity) connected to a nasal cannula with heated tubing.

DETAILED DESCRIPTION OF THE INVENTION

Osmolytes are well-known therapeutics in the field of respiratory therapeutics. These agents are molecules or compounds that are osmotically active (i.e., are “osmolytes”). “Osmotically active” compounds of the present invention are membrane-impermeable (i.e., essentially non-absorbable) on the airway or pulmonary epithelial surface. The terms “airway surface” and “pulmonary surface,” as used herein, include pulmonary airway surfaces such as the bronchi and bronchioles, alveolar surfaces, and nasal and sinus surfaces. Active compounds of the present invention may be ionic osmolytes (i.e., salts), or may be non-ionic osmolytes (i.e., sugars, sugar alcohols, and organic osmolytes). It is specifically intended that both racemic forms of the active compounds that are racemic in nature are included in the group of active compounds that are useful in the present invention. It is to be noted that all racemates, enantiomers, diastereomers, tautomers, polymorphs and pseudopolymorphs and racemic mixtures of the osmotically active compounds are embraced by the present invention.

Active osmolytes useful in the present invention that are ionic osmolytes include any salt of a pharmaceutically acceptable anion and a pharmaceutically acceptable cation. Preferably, either (or both) of the anion and cation are non-absorbable (i.e., osmotically active and not subject to rapid active transport) in relation to the airway surfaces to which they are administered. Such compounds include but are not limited to anions and cations that are contained in FDA approved commercially marketed salts, see, e.g., <i>Remington: The Science and Practice of Pharmacy</i>, Vol. 11, pg. 1457 (19^thEd. 1995), incorporated herein by reference, and can be used in any combination including their conventional combinations.

Pharmaceutically acceptable osmotically active anions that can be used to carry out the present invention include, but are not limited to, acetate, benzenesulfonate, benzoate, bicarbonate, bitartrate, bromide, calcium edetate, camsylate (camphorsulfonate), carbonate, chloride, citrate, dihydrochloride, edetate, edisylate (1,2-ethanedisulfonate), estolate (lauryl sulfate), esylate (1,2-ethanedisulfonate), fumarate, gluceptate, gluconate, glutamate, glycollylarsanilate (p-glycollamidophenylarsonate), hexylresorcinate, hydrabamine (N,N′-Di(dehydroabietyl)ethylenediamine), hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isethionate, lactate, lactobionate, malate, maleate, mandelate, mesylate, methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate, nitrte, pamoate (embonate), pantothenate, phosphate or diphosphate, polygalacturonate, salicylate, stearate, subacetate, succinate, sulfate, tannate, tartrate, teoclate (8-chlorotheophyllinate), triethiodide, bicarbonate, etc. Particularly preferred anions include chloride sulfate, nitrate, gluconate, iodide, bicarbonate, bromide, and phosphate.

Pharmaceutically acceptable cations that can be used to carry out the present invention include, but are not limited to, organic cations such as benzathine (N,N′-dibenzylethylenediamine), chloroprocaine, choline, diethanolamine, ethylenediamine, meglumine (N-methyl D-glucamine), procaine, D-lysine, L-lysine, D-arginine, L-arginine, triethylammonium, N-methyl D-glycerol, and the like. Particularly preferred organic cations are 3-carbon, 4-carbon, 5-carbon and 6-carbon organic cations. Metallic cations useful in the practice of the present invention include but are not limited to aluminum, calcium, lithium, magnesium, potassium, sodium, zinc, iron, ammonium, and the like. Particularly preferred cations include sodium, potassium, choline, lithium, meglumine, D-lysine, ammonium, magnesium, and calcium.

Specific examples of osmotically active salts that may be used with the sodium channel blockers described herein to carry out the present invention include, but are not limited to, sodium chloride, potassium chloride, choline chloride, choline iodide, lithium chloride, meglumine chloride, L-lysine chloride, D-lysine chloride, ammonium chloride, potassium sulfate, potassium nitrate, potassium gluconate, potassium iodide, ferric chloride, ferrous chloride, potassium bromide, etc. Either a single salt or a combination of different osmotically active salts may be used to carry out the present invention. Combinations of different salts are preferred. When different salts are used, one of the anion or cation may be the same among the differing salts.

Osmotically active compounds of the present invention also include non-ionic osmolytes such as sugars, sugar-alcohols, and organic osmolytes. Sugars and sugar-alcohols useful in the practice of the present invention include but are not limited to 3-carbon sugars (e.g., glycerol, dihydroxyacetone); 4-carbon sugars (e.g., both the D and L forms of erythrose, threose, and erythrulose); 5-carbon sugars (e.g., both the D and L forms of ribose, arabinose, xylose, lyxose, psicose, fructose, sorbose, and tagatose); and 6-carbon sugars (e.g., both the D- and L-forms of altose, allose, glucose, mannose, gulose, idose, galactose, and talose, and the D- and L-forms of allo-heptulose, allo-hepulose, gluco-heptulose, manno-heptulose, gulo-heptulose, ido-heptulose, galacto-heptulose, talo-heptulose). Additional sugars useful in the practice of the present invention include raffinose, raffinose series oligosaccharides, and stachyose. Both the D- and L-forms of the reduced form of each sugar/sugar alcohol useful in the present invention are also active compounds within the scope of the invention. For example, glucose, when reduced, becomes sorbitol; within the scope of the invention, sorbitol and other reduced forms of sugar/sugar alcohols (e.g., mannitol, dulcitol, arabitol) are accordingly active compounds of the present invention.

Osmotically active compounds of the present invention additionally include the family of non-ionic osmolytes termed “organic osmolytes.” The term “organic osmolytes” is generally used to refer to molecules used to control intracellular osmolality in the kidney. See e.g., J. S. Handler et al., <i>Comp. Biochem. Physiol, </i>117, 301-306 (1997); M. Burg, <i>Am. J. Physiol. </i>268, F983-F996 (1995), each incorporated herein by reference. Although the inventor does not wish to be bound to any particular theory of the invention, it appears that these organic osmolytes are useful in controlling extracellular volume on the airway/pulmonary surface. Organic osmolytes useful as active compounds in the present invention include but are not limited to three major classes of compounds: polyols (polyhydric alcohols), methylamines, and amino acids. The polyol organic osmolytes considered useful in the practice of this invention include, but are not limited to, inositol, myo-inositol, and sorbitol. The methylamine organic osmolytes useful in the practice of the invention include, but are not limited to, choline, betaine, carnitine (L-, D- and DL-forms), phosphorylcholine, lyso-phosphorylcholine, glycerophosphorylcholine, creatine, and creatine phosphate. The amino acid organic osmolytes of the invention include, but are not limited to, the D- and L-forms of glycine, alanine, glutamine, glutamate, aspartate, proline and taurine. Additional osmolytes useful in the practice of the invention include tihulose and sarcosine. Mammalian organic osmolytes are preferred, with human organic osmolytes being most preferred. However, certain organic osmolytes are of bacterial, yeast, and marine animal origin, and these compounds are also useful active compounds within the scope of the present invention.

Under certain circumstances, an osmolyte precursor may be administered to the subject. Accordingly, these compounds are also useful in the practice of the invention. The term “osmolyte precursor” as used herein refers to a compound which is converted into an osmolyte by a metabolic step, either catabolic or anabolic. The osmolyte precursors of this invention include, but are not limited to, glucose, glucose polymers, glycerol, choline, phosphatidylcholine, lyso-phosphatidylcholine and inorganic phosphates, which are precursors of polyols and methylamines. Precursors of amino acid osmolytes within the scope of this invention include proteins, peptides, and polyamino acids, which are hydrolyzed to yield osmolyte amino acids, and metabolic precursors which can be converted into osmolyte amino acids by a metabolic step such as transamination. For example, a precursor of the amino acid glutamine is poly-L-glutamine, and a precursor of glutamate is poly-L-glutamic acid.

Also included within the scope of this invention are chemically modified osmolytes or osmolyte precursors. Such chemical modifications involve linking to the osmolyte (or precursor) an additional chemical group which alters or enhances the effect of the osmolyte or osmolyte precursor (e.g., inhibits degradation of the osmolyte molecule). Such chemical modifications have been utilized with drugs or prodrugs and are known in the art. (See, for example, U.S. Pat. Nos. 4,479,932 and 4,540,564; Shek, E. et al., <i>J. Med. Chem. </i>19:113-117 (1976); Bodor, N. et al., <i>J. Pharm. Sci. </i>67:1045-1050 (1978); Bodor, N. et al., <i>J. Med. Chem. </i>26:313-318 (1983); Bodor, N. et al., <i>J. Pharm. Sci. </i>75:29-35 (1986), each incorporated herein by reference.

In general, osmotically active compounds of the present invention (both ionic and non-ionic) that do not promote, or in fact deter or retard bacterial growth, are preferred.

It is an object of the present invention to provide a nebulizer connected to a nasal cannula to deliver aerosolized osmolytes (e.g., HS) to subjects over long time intervals. The nebulizer will have the capacity for a large volume of osmolyte solution (up to 2 liters) and will produce aerosol particles in the respirable range (1-5 microns MMAD) at a rate that will produce good lung deposition and will be continuous, i.e. will not require refilling over long time periods (8-24 hrs). An example of such a nebulizer is the Westmed Heart High Output Nebulizer. A nasal cannula/tubing will be connected to the nebulizer by a tapered fitting. The tubing will have an inner diameter of ˜3-5 mm with a length of 2-4 meters. The end of the tubing may end in one or two tapered ends that fit into the nostrils, although face masks are alternatives.

Both nebulizers and nasal cannulas are well-known in the field of respiratory treatment. See <i>Critical Care Medicine </i>(Michael James Murray, American Society of Critical Care Anesthesiologists, Douglas B. Coursin, Ronald G. Pearl, Donald S. Prough), pp. 431 and 439-445. However, commercial nebulizers are generally designed to rapidly delivery therapeutic agents via the mouth or mask. Nasal cannulas are generally used to delivery oxygen (gasses) to the lungs through the nose. Nasal cannulas are preferred for the delivery of gasses as they are comfortable to wear for long periods of time. The adaptation of a nasal cannula on a nebulizer provides a novel means to deliver inhaled osmolytes that offers the following advantages. (1) The nasal cannula/nebulizer device is comfortable and can be worn for extended periods of time. (2) The device can deliver osmolytes for long periods of time, thus, increasing the therapeutic benefit of these treatments.

Due to the narrow diameter of oxygen tubing and nasal cannulas, the output from a nebulizer will lead to the deposition of aerosol on the inner surface of the tubing, leading to the “condensation” and accumulation of fluid droplets. Fluid inside the tubing can occlude the flow of aerosol inside the tubing, as well as, result droplets blowing out the nasal cannula that would “drown” the subject with boluses of liquid.

Several modifications improve the performance of the nasal cannula/nebulizer device to prevent fluid condensation on the inner surface of the tubing and nasal cannula. It is an object of the present invention to heat all the fittings, tubing, and/or the nasal cannula of the device to retard condensation in the tubing. Thus the heated, inner surface coated cannula will ensure that the aerosol generated will be delivered to the nostril as a respirable particle. It is another object of the present invention that the tubing will contain a coating on its inner surface so as to prevent condensation of solution in the lumen. It is anticipated that the subject will use the heated cannulae to receive HS for periods of minutes to daily.

EXAMPLES

The nebulizer system shown in <figref idrefs="DRAWINGS">FIG. 1</figref> was run for 80 minutes with 7% hypertonic saline. The build-up of fluid within the oxygen tubing was observed with and without heating the oxygen tubing in a water bath. For this system, the tubing became occluded with water droplets within 23 minutes of continuous nebulizer operation. Externally heating the tubing to 60° C. allow the nebulizer system to run for the full 80 minutes without occlusion from water droplets.

<tables id="TABLE-US-00001" num="00001"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="1"><colspec colname="1" colwidth="217pt" align="center" /><thead><row><entry namest="1" nameend="1" rowsep="1">TABLE 1</entry></row></thead><tbody valign="top"><row><entry namest="1" nameend="1" align="center" rowsep="1" /></row><row><entry>The effect of heating on fluid condensation within the oxygen tubing.</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="4"><colspec colname="1" colwidth="63pt" align="center" /><colspec colname="2" colwidth="49pt" align="center" /><colspec colname="3" colwidth="56pt" align="center" /><colspec colname="4" colwidth="49pt" align="center" /><tbody valign="top"><row><entry>Nebulizer/</entry><entry /><entry>External Tubing</entry><entry>Time to</entry></row><row><entry>Compressor</entry><entry>Tubing</entry><entry>Temperature</entry><entry>Condensation</entry></row><row><entry namest="1" nameend="4" align="center" rowsep="1" /></row><row><entry>Pari-LC Star with</entry><entry>Oxygen Tubing</entry><entry>Ambient</entry><entry>23 min</entry></row><row><entry>ProNeb Compressor</entry><entry>with Adult</entry></row><row><entry /><entry>nasal cannula</entry></row><row><entry>Pari-LC Star with</entry><entry>Oxygen Tubing</entry><entry>60° C.</entry><entry>No significant</entry></row><row><entry>ProNeb Compressor</entry><entry>with Adult</entry><entry /><entry>condensation</entry></row><row><entry /><entry>nasal cannula</entry></row><row><entry namest="1" nameend="4" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.